Magnetic components, such as reactors and motors, are used in various fields. As such a magnetic component, for example, JP 2012-119454A discloses a reactor used for a converter of a hybrid automobile.
JP 2012-119454A discloses a reactor used for a converter installed in a vehicle such as a hybrid automobile, the reactor including a coil that is formed by helically winding a wire and a magnetic core that is formed into a ring shape by combining together a plurality of powder compacts (core pieces for the reactor) obtained by compression molding a raw material powder containing a soft magnetic powder. Also, J P 2012-119454A discloses a core component in which powder compacts are individually covered with respective insulating coating layers (resin-molded portions), a core component in which a plurality of powder compacts are collectively covered with a resin-molded portion, and the like.
There is a demand for a core component having excellent joinability between a powder compact and a resin-molded portion.
A coil included in a magnetic component such as a reactor generates heat through Joule heating when energized and does not generate heat when not energized. In particular, when the energizing current value is large as in the case of a reactor or the like used in an in-vehicle converter, the coil generates a large amount of heat. Accordingly, a powder compact and a resin-molded portion that are disposed near the coil thermally expand and contract due to heat cycles caused by the coil. Since the powder compact, which is mainly composed of a metal such as iron, and a resin have different coefficients of thermal expansion, there is a risk that the thermal expansion and contraction may cause the resin-molded portion to peel from the powder compact. If the resin-molded portion peels, for example, there is a possibility that insulation between the powder compact and the coil will become insufficient, and there is a possibility that the gap length provided between powder compacts will change. If such a problem occurs, the magnetic characteristics of the reactor are impaired. Moreover, if the resin-molded portion peels, and the plurality of powder compacts are not sufficiently integrated, there is a risk that the resonance frequency may change prior to and after peeling, and thus vibration and noise may increase compared with those prior to peeling.
The present invention was made in view of the above-described circumstances, and an object thereof is to provide a core component in which a powder compact and a resin-molded portion are strongly joined to each other. Another object of the present invention is to provide a method for manufacturing a core component in which the joinability to a resin-molded portion is excellent. Moreover, another object of the present invention is to provide a reactor that uses a core component in which the joinability to a resin-molded portion is excellent.